Samsung C8249 用户手册
8-BIT TIMER A/B
S3C8245/P8245/C8249/P8249
11-10
F
PROGRAMMING TIP — To generate a one pulse signal through P3.0
This example sets Timer B to the one shot mode, sets the oscillation frequency as the Timer B clock source, and
TBDATAH and TBDATAL to make a 40
TBDATAH and TBDATAL to make a 40
µ
s width pulse. The program parameters are:
40
µ
s
— Timer B is used in one shot mode
— Oscillation frequency is 4 MHz (1 clock = 0.25
µ
s)
— TBDATAH = 40
µ
s / 0.25
µ
s = 160, TBDATAL = 1
— Set P3.0 to TBPWM mode
ORG
0100H
;
Reset address
START
DI
•
•
•
LD
TBDATAH,# (160-2)
;
Set 40
µ
s
LD
TBDATAL,# 1
;
Set any value except 00H
LD
TBCON,#00000001B
;
Clock Source
←
f
OSC
;
Disable Timer B interrupt.
;
Select one shot mode for Timer B.
; Stop Timer B operation.
; Set Timer B output flip-flop (TBOF) high
; Set Timer B output flip-flop (TBOF) high
LD
P3CONL, #02H
;
Set P3.0 to TBPWM mode.
•
•
Pulse_out:
LD
TBCON,#00000101B
;
Start Timer B operation
; to make the pulse at this point.
•
;
After the instruction is executed, 0.75
µ
s is required
•
;
before the falling edge of the pulse starts.
•